Camera film threading mechanism



Oc't. 7, 1947. F. E. BIDDLE ETAL 2,428,349

CAMERA FILM THREADIG MECHANISM Filed JuneO, 1945 5 Sheets-Sheet l /N VEN TOR FIG. 6 FRANK E. IDDLE e CONRAD O.ROGNE JH.

BY mf@ 4 %f ATTORNE l Oct.'7, `1947. F. E. BIDDLE ErAL CAMERA FILM THREADING MECHANISM 5 Sheets-Sheet 2 Filed June 30, 1945 /NvE/v'roRs l FRANK E. EIDDLE' & CONRAD O. ROGNE JR A ATTO RNE Y F. E. BIDDLE ETAL CAMERA FILM THREADING MECHANISM Filed June v5o, 1945 5 sheets-sheet, s

60 [-2 l 7/ A @y 23 Q 2 2 m [a4 I l 106% 2/ la7` 22 103-` '2"53" M 6l IN VEN TORS n FRANK EBIUDLE 6( CONRAD o ROGNE JR.

' AT ORN EY Oct. 7, 1947. F, E. BIDDLE ETAL 2,428,349

CAMERA FILM THREADING MECHANISM -Filed June 30, 1945 5 Sheets-Sheet 4 /NVENTORS FRANK E BIDDLE l CNRAD 0 ROGNE JR Och 7, 1947 F. E..B|DD1 E ETAL 2,428,349

CAMERA FILM THREADIG' MECHANISM 5 Sheets-Shea?l 5 Filed June so, 1945' /NvENToRs FRANK E'. BIDDLE CONRAD O. ROGNE JR.

Patented Oct. 7, 1947 UNITED STATES PATENT oFFicE A CAMERA FILM THREDING MECHANISM Frank E. Biddle and Conrad O. Rogne, Jr., Los

Angeles, Calif., assignors, by mesne assignments, to Warner Bros. Pictures, Inc., New York, N. Y., a corporation of Delaware Application June 30, 1945, Serial No. 602,484

4 Claims. 1

The invention relates to a camera and more particularly to an improved apparatus for threading motion picture lm in the camera.

The invention provides an improved lm threading arrangement wherein the iilm may be traversed from the supply reel to the takeup reel through the gate with the use of only two sprockets, namely a feed sprocket and a take-up sprocket, without the use of guide rollers. Film guides for those sprockets are of such shape and position as to guide the film in a free loop at the leading and trailing sides of the gate, with a con trol handle for operating both lm guides and the gate. Preferably the threading device is carried by a movement mounting plate which carries the film gate and the pull-down mechanism, whereby the supply and take-up sprockets, the movable gate member, the pull-down mechanism and the threading device are mounted as a unit on the movement mounting plate, for ease in assembly and repair.

For further details of the invention, reference may be made to the drawings wherein Figs. 1 and 2 are front and rear views in perspective of a motion picture camera embodying the present invention. Y

Fig. 3 is a view in elevation of the camera of Figs. 1 and 2 with parts broken away, with a portion of the film gate shown in section, and with the door of the camera removed.

Fig. 4 is a sectional view on line 4-4 of Fig. 3.

Fig. 5 is a sectional view on line 5 5 of Fig. 3.

Fig. 6 is a horizontal sectional view on line '6 6 of Fig. 3.

Fig. 7 is a view corresponding to Fig. 3 on a smaller scale, with the film reels and movement mounting plate removed. f

Fig. 8 is a view in elevation of the rear of the movement mounting plate.

Fig. 9 is a view in elevation of the inside of the cover of the camera, on the same scale as Fig. 7.

Fig. 10 is an enlarged perspective view of the movement mounting plate removed from the camera.

Referring in detail to the drawings, the camera 'I'he lens turret 9 is provided with a suitable pho-L tographing lens I II although additional lenses maybe employed. The camera may be held in the hand or secured t0 a suitable support II.

As shown in Fig. 3, secured to the back wall l2 of the camera is a movement mounting plate I3,

Referring particularly to Fig. 3, the lm 2.0

from the supply reel 2 is led under the bottom and across the front upwardly from a supply sprocket 2I by a film guide 22. The lm 20 is threaded in a free loop 23 between the sprocket 2I and the entrance of iilm gate 24, then downwardly through this gate, in a free loop 25 at the exit side of the gate, then upwardly across the iront and top of the take-up sprocket 26 and then directly to the take-up reel 3. The ilm 20is held on the front and top of sprocket 26 by a lm guidel 21 similar in shape to film guide 22 but reversed casing I houses the lm supply reel 2 above the in position. The intermediate portion of each film guide 22 and 2l is concentric to its sprocket, while its opposite ends flare out, the rear end oi guide 22 forming one end of a lever 28 pivoted to the movement mounting plate I3 at 29 at Vthe rear of and slightly below the axis of sprocket 2I. Lever '28 has on the same side of pivot 23 as the film guide 22, a lever arm 30 having a slot 3l engaged by a pin -32 on a threading plate 33.

- Film guide 2l is similarly constructed and forms, one arm of a lever pivoted at 34 to the movement mounting plate I3, at the rear of and slightly above the axis of sprocket 26. Film guide 2l similarly has a lever arm 35 having a slot 36 engaged by a pin 3l on the threading plate 33.

The front of the casing I has an aperture body 38 carrying an aperture plate 39 having anexposure aperture 40.

Secured to the threading plate 33 is a back plate 4I having a pressure pad 42 to hold the lm flatv 0n the aperture plate 39. v

As shown in Fig. 10, the pressure pad 42 has vertical side rails 43 and 44 on which the edges of the film ride, the pad 42 carrying a plurality of rollers 45. The pad v42 is removably held in an opening 46 in the back plate 4| by means of a horizontal leaf spring not shown, the free end of which bears against the rear plate 41 of the pad 42, and the other end of which is suitably secured to a rear extension of the edge guide plate 48 which is suitably fixed to the back plate 4|. The edge guide plate 48 at the front 49 thereof projects forwardly of the back plate 4| and serves as a straight edge against which the rear edge of the film rides.

As shown in Fig. 10, the lower portion 50 of the back plate is curved and provided with a slot 5| through which the claw 52 projects.

In front of back plate 50 is a similarly curved front plate 53 having a slot 54 like slotI 5|, through which the claw 52 projects when curved plate 53 is parallel to back plate 50, being urged in that position to dene a channel for the lm through the lower portion of the nlm gate, as shown in Fig. `3, by a spring 55, the front end of which is secured to the camera body as indicated at 56, and the free end 51 of which rests on the upper portion of the curved plate 53. The curved plate 53 1s pivoted on a horizontal axle 58 carried by the lower front corner of the movement mounting plate I3. The rearward movement of curved plate 53 under action of the spring 55 is limited by a stop 59 on the movement mounting plate I3. The curved pressure plate 53 has a central depressed portion 53 to avoid scratching the emulsion, the sides of plate 53 holding the face edge portion of the film against the opposite sides of the back plate 50.

The spring, not shown, acting on the pressure pad 42 is comparatively weak to avoid applying enough pressure to the lm to scratch the emulsion, whereas the strength of spring 55 is greater so that curved plate 53 will hold the longitudinal edges of the f'llm against the front of the curved back plate 50.

When the camera is first set into operation, if the claw 52 does not engage a sprocket hole but instead engages an imperforate portion of the edge of the film, the spring 55 permits the claw to push both the film and the curved plate 53 away from the curved portion 50 of the back plate, the claw traveling downwardly until it slides into a sprocket hole, whereupon the spring 55 urges the curved plate 53 forwardly to push the film onto the claw 52.

As shown in Fig. 3, the claw 52 is at the front end of an arm, the 'rear end of which has a rocklng slide pivot 60 and an intermediate cam 6| on a cam shaft 62 (see Figs. 4 and 6). Cam shaft 62 has a bearing sleeve 63 held in the movement mounting plate I3 by a nut 64. Cam shaft 62 has a gear 86 in a recess 65 at the back of the movement mounting plate |3. Behind gear 66 is a y wheel 61. Cam shaft 62 carries a ball-bearing 68 which slidably lits in an aperture 69 in the 'offset back wall 10 of the camera. Cam shaft l2 terminates rearwardly in a beveled gear 1| which meshes with a driven beveled gear 12 on power shaft 13 having shutter gear 14 at its front end, and a gear 15 at its rear end. Gear 15 is driven by the motor gear 16. Gear 16 is carried by motor casing 4 and the latter is removably` held on the camera casing extension 11 by suitable screws 18. l

Fig. 1 illustrates the aperture 69 in back of which is the driven gear 12. Bearing 68 slides 4 into and out of aperture 69 when movement mounting plate I3 is assembled on or removed from the back wall I2.

Referring to Fig. 8, which shows the rear of the movement mounting plate |3, the cam spur gear 66 meshes with spur gear 19 which is secured to and drives the supply sprocket 2| (see also Fig. 4), and gear 19 drives gear 80 carried by the movement mounting plate I3. The footage indicator 8| shown in Fig, 4, may be coupled to the gear 80.

At the other side of cam gear 66 is gear 82 fixed to the take-up sprocket 26. The gears 66, 19, B0 and 82 are all spur gears and are rotatably carried by the movement mounting plate I3. Plate I3 at its lower rear portion, as shown at 83, is cut away so that gear 82 will mesh with a pinion 84 (see Fig. 1) rotatably carried by the back wall I2 of the camera, pinion 84 meshing with a gear 85 which drives the take-up reel 3.

As shown in Fig. 5, gear 85 is Coupled to takeup reel 3 by a friction drive here illustrated as comprising tubular shaft 86, the left end of which is of comparatively large diameter and mounted in a bearing 81 and held by the head of an end screw 88.

The enlarged end of shaft 86 has integral therewith a friction disk 89 and the gear 85 is rotatable on the shaft 86 and clamped between friction disk 89 and a spring pressed plate 90 carrying a pin 9| which extends through a slot 92 in shaft 83. Bearing on pin 9| is a plunger 93 acted on by a spring 94 having a screw plug `95. Takeup reel 3 has a non-circular coupling 96 (see Fig. 3) with the brake member 90. As shown in Figs. 4, 5, 6, '7, and 9, arising from the back wall I2 is a side wall 91 having a stepped continuous rim 98 intertting with the rim 99 on a door |00. The door |00 may be locked in position on the casing I by means of a suitable lock device |0| having a handle |I9 and lock bolts such as |02 engaging apertures such as |02 in the rim `98 of the casing.

In order to hold the rear edge of the lm against the edge guide plate 49 (see Fig. 10) the door |00 carries a fiat straight movable edge guide plate |03 which as shown in Fig. 4, is slidably carried at its upper and lower ends by posts |04, |05 on the door |00. Bearing against the opposite ends of the movable edge guide |03 is a bow spring |06, the central portion of which is suitably secured to the inside of door |00 by means such as screws |01. As shown in Fig. 6, the edge guide |03 is of substantial width and as shown in Fig. 4 it extends lengthwise from the top of the back plate 4| to a point adjacent the take-up sprocket 26 and hence as will appear from Fig. 3, the edge guide |63 extends over the straight as well as the curved portion 50 of the back plate 4|. The spring pressed edge guide |03, when door vI|l0 is closed, is parallel to the relatively fixed edge guide plate 49. The back plate 50, aperture plate 39, and curved pressure plate 53 are slightly narrower than the film, in fact .004 inch narrower than fresh nlm and aboutlOOl Ainch narrower than old film which has shrunk. Hence pressure edge guide |03 rides on and applies pressure to the front edge of the film to urge the rear edge of the lm against fixed edge guide plate 49, through a lm channel whereof the upper portion is spring pressed forwardly by the pressure pad 42 and the lower portion is spring pressed rearwardly by the curved plate 53. Y

As shown in Figs. 4, 6 and 9, at the rear of edge guide |03 is a lug |08 inwardly projecting from the inside of door |00. The front of lug |08 is flat as shown at |09 in Fig. 9 to extend adjacent the rear of back plate 4| and hold the latter in closed position shown in Figs. 'Sand 6 to define a channel for the film. f'r Lug I08falso prevents the door from being-closed if back plate v4| is in open position, as in this event the end of lug |08 would engage the side of back plate 4I and prevent closure of the door. v

Threading plate 33 'is' slidably mounted on movement mounting plate I3, for movement in a straight line, whereas the axes of cam 6I and pivot bearing 60 are fixed in the movement mounting plate. To allow threading plate 33 to slide relatively to plate I3, threading plate 33 has an enlarged aperture I I0 through which the cam i shaft 62 and slide pivot bearing 60 project.

shanks of three screws H4, I I and II6, respectively, having heads wider than said slots. Threading plate 33 is moved back and forth by a handle II8.

When handle I|8 is moved to the right as shown in Fig. 3, the back plate 4I is moved rearwardly to open position and lm guides 22 and 21 are swung towards each other and forwardly away from the front of `their respective sprockets 2| and 26, to open a channel for the film and permit the film to be threaded on those sprockets and through the gate 24. After the film has been threaded, with free loops 23 and 25, as shown in Fig. 3, the handle I I8 is moved to the left to close the back plate 4I and pivot film guides 22 and 21 away from each other and rearwardly to the closed positions shown in Fig. 3.

The back plate r4I is held in closed position shown in Fig. 3 not only by the door lug |08, but also by friction due to the heads of screws I I4 to I|6 engaging the face of threading plate 33. Screws I4 to I IE are threaded into plate I3.

It will be noted that no pilot or register pins are employed. The film is prevented from overrunning or overthrowing the claw 52 due to the friction in the gate provided by the pressure pad 42 and more particularly by the friction due to the front pressure plate 53.

The invention provides a unit construction wherein substantially all of the film traversing mechanism including the threading device, is mounted on the removable movement mounting plate I3 for ease of assembly and repair. Also it is simply necessary to operate a single handle I I8 to open or close the threading channel through the sprockets and gate.

A compact arrangement with the supply and take-up reels 2 and 3 close together and close to the front of the camera is provided by supporting these reels with the rear flanges thereof offset from the back wall I2 of the camera, as shown in Fig. 5, whereby the reels 2 and 3 overlap certain rear portions of the movement mounting plate 3 as shown in Fig. 3, with the rear end of threading plate 33 and handle I8 extending in the space between reels 2 and 3 as shown in Fig. 3.

The edge guide feature is disclosed and claimed in application S. N. 602,483, filed June 30, 1945, for Film guide for camera. The front pressure plate feature is disclosed and zclaimed in application S. N. 602,482, filed June 30, 1945, for Film gate for camera.

It will be apparent that various modications may be made in the invention without departing from the spirit of the following claims,

We claim: Y

:1. Film threading apparatus for a moving picture machine having an aperture plate, said apparatus comprising a movement mounting plate, supplyand take up sprockets carried by said movement mounting plate, a claw device carried by said movement mounting plate, a.y support slidable on said movement mounting plate, a back plate on said support for said aperture plate, a movable film guide for leading the lm around the front of said supply sprocket, a movable film guide for leading the nlm around the front of said take up sprocket, and a mechanical movement between said support and each of said film guides for moving said film guides towards the front away from said sprockets by movement of said support when said support is moved to the rear to carry said back plate to open position and for moving said film guides towards the rear to hold the film on said sprockets by movement of said support when said support and :back plate are moved to the front.

2. Film threading apparatus for a moving picture machine having film supply and take up reels, supply and take up sprockets, and a lm gate having a movable back plate, said apparatus comprising a lm guide at the front of each of said sprockets, each of said film guides comprising guide portions leading the nlm tangentially to and from its sprocket, said lm guides providing a path for the film directly between said reels and said sprockets, and directly in a free loop between said sprockets and said gate, and a mechanical movement between each of said film guides and said back plate for moving said film guides forwardly onto their sprockets by rearward movement of said back plate and vice versa.

3. Film threading apparatus for a moving picture machine having an aperture plate and a back wall, an aperture in said wall, a driven gear opposite said aperture behind said wall, a movement mounting plate, supply and take up sprockets carried by said movement mounting plate, a :claw device and cam shaft therefor carried by said movement mounting plate, said lcam shaft terminating in a gear for said driven gear, gearing on said movement mounting plate between said cam shaft and said sprockets, a bracket slidable on the front of said movement mounting plate, a back plate on said :bracket for said aperture plate, a movable nlm guide for leading the film across the front of said sup-ply sprocket, a movable film guide for leading the film across the front of said take up sprocket, a pivotal support for each of said film guides on said movement mounting plate, and a pin and slot connection between each of said film guides and said bracket for moving said film guides by movement of said bracket.

et. Film threading apparatus for a moving picture machine having an aperture plate and a back wall, an aperture in said wall, a driven bevel gear opposite said aperture behind said wall, a movement mounting plate, means removably securing said Kmovement mounting plate to said back wall, a claw device and cam shaft therefor carried by said movement mounting plate, said cam shaft terminating in a bevel gear for said driven gear, gearing on said movement mounting plate between said cam shaft and said sprockets, a movable film guide facing each of said sprockets, said fil-m guides being movable to one position to hold the film on said sprockets and movable to another position to permit threading REFERENCES CITED A The following references are of record in the le of this patent:

Number Number UNITED STATES PATENTS Name Date Howell Aug, 2, 1927 Frenzel Jan.2,1934 Lechleitner et al. June 4, 1940 FOREIGN PATENTS Country Date Great Britain Nov. 23, 1933 Great Britain May 10, 1934 

